Medical infusion apparatus including safety valve

Abstract

Medical infusion apparatus includes a container for a liquid to be infused, tubing leading from the container to the subject to receive an infusion, a pump for pumping the infusion liquid via the tubing to the subject, and a safety valve connected in the tubing between the pump and the subject. The safety valve is normally closed to prevent free-flow of the liquid from the container, but is automatically opened when a predetermined minimum pressure is applied to the liquid by the pump. The safety valve is also manually deformable to open the valve and to permit priming the apparatus.

We claim: 
     
       1. Medical infusion apparatus, comprising: a container for a liquid to be infused; tubing leading from the container to the subject to receive an infusion; a pump for pumping the infusion liquid via said tubing to the subject; and a safety valve connected in said tubing between said pump and the subject; said safety valve being normally closed to prevent free-flow of the liquid from the container but being automatically opened when a predetermined minimum pressure is applied to the liquid by said pump, wherein said safety valve comprises: a cannula having an axial passageway from one end of the cannula but closed at an opposite end, and a radial bare adjacent said opposite end leading from said axial passageway to an outer surface of the cannula; and an elastomeric sleeve around the cannula and overlying and normally closing said radial bore, wherein said safety valve is adapted for external manual deformation to open the valve and to permit priming of the apparatus. 
     
     
       2. The apparatus according to claim 1, wherein said cannula includes an annular seat at both ends for receiving said tubing in order to connect two sections of said tubing together with the safety valve in between. 
     
     
       3. The apparatus according to claim 1, wherein the outer surface of said opposite end of the cannula is formed with a ribbed formation for locating said elastomeric sleeve. 
     
     
       4. Medical infusion apparatus, comprising: a container for a liquid to be infused; tubing leading from the container to the subject to receive an infusion; a pump for pumping the infusion liquid via said tubing to the subject; and a safety valve connected in said tubing between said pump and the subject; said safety valve being normally closed to prevent free-flow of the liquid from the container but being automatically opened when a predetermined minimum pressure is applied to the liquid by said pump; said safety valve also being manually deformable to open the valve and to permit priming of the apparatus, wherein said safety valve comprises: a cannula having an axial passageway from one end of the cannula but closed at an opposite end, and a radial bore adjacent said opposite end leading from said axial passageway to the outer surface of the cannula; and an elastomeric sleeve around the cannula and overlying and normally closing said radial bore, further including a lubricant between the outer surface of the cannula and the inner surface of the elastomeric sleeve.